Nyloc Lock Nuts M4–M10 — A4 Marine 316 Stainless DIN 982

FAS-NYLOC-A4-M4-1

£2.95

Nut Size

Pack Size

Why choose these A4 Marine Nyloc Lock Nuts

Our A4 Marine Nyloc Lock Nuts are precision-formed from A4 (316) marine grade stainless steel to DIN 982 — the European standard for full-height (high-form) nylon insert hex nuts. A4-316 contains added molybdenum that gives substantially better resistance to chloride corrosion than the A2 grade, making it the right choice for boats, marine fittings, swimming pools and any installation exposed to salt water, salt air or de-icing salts. As the bolt thread engages the nut it cuts through the unthreaded nylon collar, generating an interference fit that resists vibration loosening across a wide temperature range.

Sizes available

M4 / 4mm — brackets, panels and small fittings
M5 / 5mm — fittings, signage and trim
M6 / 6mm — handrails, fencing and deck hardware
M8 / 8mm — deck cleats, stanchions, trailer and machinery fixings
M10 / 10mm — structural marine fixings and heavy-duty installations

Pack options

Each size is available as a single unit sample, or in a pack of 10. Use the variation selectors above to choose the exact combination you need.

Typical uses

Boatbuilding, deck fittings, stanchions, cleats and bow-rail joints
Boat trailers, jetties, pontoons and outdoor pool/spa equipment
Coastal gates, fencing and architectural metalwork where chloride exposure is constant
Vehicles, trailers and machinery that are washed regularly or work in salty conditions

How to fit

Place the nut onto a standard metric bolt or stud with the plain hex face against the work surface and the nylon collar facing away from the joint. Tighten with a hex spanner or socket — the bolt thread will cut into the nylon insert as it engages, producing the locking action. Use a clean, undamaged bolt thread for best results, and replace the nut rather than re-using if the locking action feels weak.